starting off

I've been learning a new song by alex g but I hit a roadblock of finding what the chord names are and how the strumming goes. I'm trying to figure out how these notes fit into a chord. The part of the tab I'm trying to figure out is -- 12 0 12 10 8 which i think is -- B G D G C

that's how far I usually get because I don't know how to translate notes when it seems like they don't fit into a scale. Like say a Cmaj has three notes C E G. It makes sense to me because all the notes fit into the Cmaj scale. So I guess my question is how do I translate the notes -- B G D G C into the a scale and chord.